Measurement of particle concentrations in Piacenza urban area: Ambient air levels and personal exposure concentrations

Transcription

1 Measurement of particle concentrations in Piacenza urban area: Ambient air levels and personal exposure concentrations Giovanna RIPAMONTI- PhD student Environmental and infrastructural Eng.- -Politecnico di Milano, Milano Italy

2 Research background Adversehealtheffectsassociatedwithparticulateair pollution Ultrafine particleshavegainedattentionwithrecentevidenceshowingthemtobemore toxic than larger particles Air quality standard are still focused on particle mass concentrations (TPS, PM10, PM2.5) Limited knowledge on UFP, the measurement of UFP is an open field of research. Coarse and Fine particle (PM10, PM2.5) Mass concentration Ultrafine and Nanoparticles Particle number concentration 2

3 UPUPA Project: Ultrafine particle in urban Piacenza area River Po valley: area affected by sever air pollution episodes (PM air quality standard are often not attained) PM levels are continuously monitored (air quality monitoring network) Scares information on UFP levels, only few studies exist. UPUPA Project: Ultrafine particle in urban Piacenza area Investigation on ambient air UFP levels : continuos measurment at fixed station positioned at traffic exposed site and urban background site Investigation on personal exposure to UFP: measurement campaigns using portable instruments 3

4 Personal exposure measurements Outdoor concentrations measured at fixed monitoring stations? Personal Daily Exposure Transport micro-environments appear to be of particular relevance in the determination of the total daily exposure : People spend a non- negligible part of the day commuting Proximity of important sources of PM and UFP (vehicle exhaust emissions, wear of brake etc.) Direct measurement of exposure concentrations using portable instruments able to measure at high time resolution. 4

5 Personal exposure measurements To Provide quantitative information on particles exposure concentrations in transport micro-environments, by means of sampling campaigns performed with portable instruments. Three different transport modes have been investigated: BUS CAR BIKE

6 Methods: Instruments Particle number concentrations (PNC) were measured at 1-min time resolution by means of two different portable instruments: Optical Particle CounterOPC: PNC Size range: 0,300-10,0 μm size resolved data 8 intervals Fine & coarse particles P-Trak UFP particle counter: PNC Size range 0,020-1,0 µm-total PNC Ultrafine particles

7 Methods Period: Twoweeksin Julyand September2011 Time: Twodailysessionduringtrafficrush hour: Morning: 8:00-9:30 Evening: 17:00-18:30. Method: A route covering different city-centre trafficked roads was performed consecutively with the three transport modes. Method: The instruments were held in a backpack carried by an operator maintaining the instruments inlets near the breathing zone. During the car and bus trips the backpack was positioned on a passenger seat 7

8 Methods: Car and bike route Stradone Farnese Via IV Novembre Viale Dante Alighieri 8

9 Results: Comparison between transport modes ULTRAFINE PARTICLES High 1 min peaks ( cm -3 )were measured in all the transport mode. Similar PNC average levels characterize bike and bus mode (~ cm -3 ). Car mode presents the highest average levels (~ cm -3 ) and the most disperse 1-min values. Infiltrationand accumulationin car-cabin of direct vehicle emissions Number concentration (cm -3 ) BIKE BUS CAR MORNING EVENING

10 Results: Comparison between transport modes FINE PARTICLEs(0,3 10,0 µm) High 1 min peaks ( cm -3 ) were measured in all the transport modes. Similar PNC average levels characterize bike and car mode ( ~60-70 cm -3 ). Bus mode presents the highest average levels ( ~ cm -3 ) and the most disperse 1-min values (IQR ~150 cm -3 ). Number concentration (cm -3 ) BIKE BUS CAR MORNING EVENING

11 Results: Comparison between transport modes FINE PARTICLES (0,3 10,0 µm) BUS: - Higher presence of particles in the size range 0,5<dp<1,5 µm Infiltration in the bus cabin of diesel engine exhaust from the bus itself CAR: - Lower presence of coarse particles (dp>2,5 µm) Removal of large particles in the air ventilation system 11

12 Comparison between cycle lanes On road Green Dedicated On road 12

13 Comparison between cycle lanes PARTICOLATO ULTRAFINE Average levels 2-3 times lower for green and dedicated lanes that on-road lane. Low variability of 1-minute PNC for the green lane, with peak values 2-3 times lower than the other lanes. 13

14 Comparison between cycle lanes PARTICOLATO FINE (0,3 10,0 µm) Similarlevelsforalltypeof bike lanes; Low spatialvariabilityoffine particle concentrations 14

15 Thanks for the attention! 15